The ϕ-component, ϵϕ, of the mean electromotive force ϵ↘ generated by asymmetric flow of fluid just beneath the core-mantle boundary (CMB), is obtained using a geomagnetic field model. This analysis is based on the supposition that the axisymmetric part of fluid flow beneath the CMB is tangentially geostrophic and toroidal. For all the epochs studied, the computed ϵϕ is stronger in the southern hemisphere than that in the northern hemisphere. Assuming a linear relationship between ϵ↘ and the azimuthally averaged magnetic field B↘0, the only non-zero off-diagonal components of the pseudotensor &agr;ij, relating ϵ↘ to B↘0, are estimated as functions of colatitude &thgr; and the physical implications of the results are discussed. ¿ American Geophysical Union 1992